w0ss semi DIY powerwall V2

to add to the confusion, i DO NOT have voltage through my case...@wOss did both of your cases show voltage?

So far, I have only checked one of my three modules after seeing that post a few pages back. I did not have continuity between the negative terminal and the case suggesting to me that the case was not bonded to the negative. I still need to open the modules again and inspect them in more detail. When I do, I'll take some photos.

I received my boards the other day as well as all the parts. I started soldering them, but have yet to finish. I definitely appreciate the board and design, thanks again w0ss. Once I have the boards completed and installed, I'm looking forward to checking the cell voltages to make sure everything looks okay. Also received my Watchmon and MM8's. It was pricey, but I think it will be worth the cost.

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vegburner said:

@hydro
Would this be an option at the battery? https://www.delcity.net/store/Del-City-Manual-Reset-(Switchable),-Surface-Mount/p_811053.h_195738 ----Your terminal fuses look nice and clean.

Click to expand...

I considered a circuit breaker, but seems like a lot of folks go with fuses. No sure if there is a reason for that, I haven't looked intothe breaker specs. The costs come out to be about thesame from what I can tell.

Like many other folks,I will be using a shunt-trip breaker as my overallbattery disconnect, but am also placing a main fuse in that line as well. I guess breakers could work on each of the module strings, but like I said...based on what I've seen, fuses seem to be the common method for protection.

I agree, these terminal fuses are nice and clean. I measured the terminals on the modules and I believe these terminal fuses will fit. the holes on the terminal fuses are plenty big compared to the terminal posts on the modules. The width of the terminal fuse (about ~3/4"seems to fit through the opening on the module (~1") such that the terminal cover can be closed and no modification should be needed. I have seen references to these fuses being used on lithium batteries, but have not reliably confirmed that yet.

A few things...

I did NOT have continuity between the case and the terminals. I only bought one cell. Regretting that now that it seems these units turned out to be pretty good. Paid all that shipping cost for one item...d'oh

When I hooked up a wire harness for BattGo BG-8S (max 8 cell) monitoring, for the first set of 7S (cells 1-7) the black wire went to Pin 2 (Cell1 neg) of the LG connector. Straightforward enough. But for the second set of 7S (cells 8-14), the black wire went to Pin8 (Cell8 neg) to get proper readings for the latter half of the cells. Kind of confusing, until I recalled what w0ss mentioned earlier about the original monitoring board being split into 2 parts.

And some questions:
Did anyone see any temperature probe leads when they opened the battery cases?
Did you see where the other wires go that come from the orange harness loom...the mystery pins (1,7,13,14,18,19,20,24)?

Sojourner said:

A few things...

I did NOT have continuity between the case and the terminals. I only bought one cell. Regretting that now that it seems these units turned out to be pretty good. Paid all that shipping cost for one item...d'oh

When I hooked up a wire harness for BattGo BG-8S (max 8 cell) monitoring, for the first set of 7S (cells 1-7) the black wire went to Pin 2 (Cell1 neg) of the LG connector. Straightforward enough. But for the second set of 7S (cells 8-14), the black wire went to Pin8 (Cell8 neg) to get proper readings for the latter half of the cells. Kind of confusing, until I recalled what w0ss mentioned earlier about the original monitoring board being split into 2 parts.

And some questions:
Did anyone see any temperature probe leads when they opened the battery cases?
Did you see where the other wires go that come from the orange harness loom...the mystery pins (1,7,13,14,18,19,20,24)?

Click to expand...

I am going to take mine apart again and try to figure out why I have connectivity. I will look for a temperature probe but I assume they have them on a few of the leads.

I checked my other modules and none had continuity between the case and neg terminal.

I also finished soldering my boards and installed them to check the cell voltages. Everything looks good. The cells provided consistent voltages and appear to be well balanced.

One thing I noticed was that when I attempted to re-install the black, plastic front cover, the U50 and U51 terminals on the board were preventing the cover from fitting properly. I noticed a 1/8 or so gap indicating the terminals are sitting a bit higher relative to the components on the original board. I'm not sure if anyone else has encountered this. I used these terminals from amazon: https://www.amazon.com/gp/product/B00FZLPCKC/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1

Maybe they are a little taller than other available terminals, not sure. Its not a big deal, I'll just have to modify the cover at some point to make it fit properly... but figured I'd mention it in case others are using the same terminals.

I noticed it was a tight fit as well. I have been trying to think of another way to connect the balance wires. one thought I had was to just solder the wire right to the board.

Hey Murr, i can't send you a pm back, says your pms are disabled. i have 3 spare board if you are in need...

Thanks vegburner. I'll pm you my email

I purchased 5 of the Lg Chems from the first batch at BH. At that time, there was nothing online about them. Put the project on hold for awhile and delighted to find this thread now.

I was told at by someone at some point it was possible to interface with the existing BMS, and the units would communicate with each other. Doesn't look like anyone has had any luck?

If anyone has any of the custom boards on this thread for sale, I would be interested in purchasing them.

Anyone find a data sheet for the LGX JH3 cell ?
Even the max discharge and max charge amps for the battery packs?
later floyd

w0ss said:

View attachment 15957


Original BMS board and breakout board I designed with resettable fuses. Took advantage of the original mounting holes. They don't exactly line up but close enough for me

Click to expand...

I really like this clean, pro-looking install. I took a while this afternoon, read through your thread carefully and then realized that I had not read through carefully enough - I have a different LG chem module. Lol ! :0 My module is a 5.94 KwH 3p 10s with the N2.1 60ah cells and (2) two 8-pin connectors ([1] one of them in the pic below). Any chance you have a resource/protocol you would recommend for figuring out the pins? I have some electronics experience, am miles short of an expert, but can follow directions. Thanks in advance for any help!

a multimeter I used to figure out which pin goes to which cell for the battery you would have 11 pins one ground and 10 voltage lines to find the ground test each pin while touching the other pins one by one you might have to check a few pins before you find some voltage once you find two pins that give you voltage use one of the pins as the ground and touch the other pins if you get a voltage reading you have found the ground if not most likely the other pin of is the ground. map out the voltage of the pins 1-10 the other pins are probably temperature sensors/communications pins
I have an salvaged LG RESM with sorta the same setup mine is 7s1p 63Ah x 6 modules
Later floyd

floydR said:

a multimeter I used to figure out which pin goes to which cell for the battery you would have 11 pins one ground and 10 voltage lines to find the ground test each pin while touching the other pins one by one you might have to check a few pins before you find some voltage once you find two pins that give you voltage use one of the pins as the ground and touch the other pins if you get a voltage reading you have found the ground if not most likely the other pin of is the ground. map out the voltage of the pins 1-10 the other pins are probably temperature sensors/communications pins
I have an salvaged LG RESM with sorta the same setup mine is 7s1p 63Ah x 6 modules
Later floyd

Click to expand...

OK, thanks floydR. I'll give it a shot and then . . . probably come back with another question.


Does anyone happen to know what format the 8-pin connector is (pic is in my post above), or how I can find out what it is?

Thanks!

So, I have been working away at this and so far I have mapped this much of the two pin-outs.
I am stuck on determining what pin 2 on the L-side does. I wrote the voltages I am getting between pin 2 and a series of other knowns in the circle at the bottom left of the pic. If anyone knows or has an idea of what is happening with pin 2, please share your wisdom!

Thanks v. much for your help!

Thought the cells were in 10s ? 36v nominal
Is there a ground pin on each connector?
The cells probably alternate sides something like L ground pin1 R cell 1 pin1 L cell 2 pin2 R cell 3 pin 2 L Cell 4 pin 3 R Cell 5 pin 3 L cell 6 pin 4 R Cell7 pin4 L Cell 8 pin 5 R Cell 9 pin 5 L Cell 10 pin 6 not saying that this is how they are in the module.
You should be getting higher voltages than what is shown in pic. it may need to be charged with a balance charger at a extremely low current till all the cells reach 2.1v then can charge at a medium current till 2.5~2.8v range. then it can be charged normally.
Later floyd
ps may as well can start your own build thread

floydR said:

Thought the cells were in 10s ? 36v nominal
Is there a ground pin on each connector?
The cells probably alternate sides something like L ground pin1 R cell 1 pin1 L cell 2 pin2 R cell 3 pin 2 L Cell 4 pin 3 R Cell 5 pin 3 L cell 6 pin 4 R Cell7 pin4 L Cell 8 pin 5 R Cell 9 pin 5 L Cell 10 pin 6 not saying that this is how they are in the module.
You should be getting higher voltages than what is shown in pic. it may need to be charged with a balance charger at a extremely low current till all the cells reach 2.1v then can charge at a medium current till 2.5~2.8v range. then it can be charged normally.
Later floyd
ps may as well can start your own build thread

Click to expand...

Yes, I should have been more clear on several points.

In terms of the cell configuration - each one of my modules dissassembles into two sections, 3p 10s, and 3p 8s. I decided to start with one of the 3p 8s sections, honestly, just because it is lighter .

Thanks for the suggestion about the pins alternating back and forth - I'll go back later and see how that tests out.

As for the voltages I describe in my last post where I am trying to figure out pin 2, I should have been clearer on that, too:

each set of (3) parallel cells has ~3.4 V. The trouble I am having with pin 2 is that I am getting only half that voltage when I test pin 2 with several of the the bus bar points, e.g. pin 2 - R side CV1: 1.7V and pin 2 - R sideCV2: 1.8V. It's as if somehow pin 2 cuts one of the cell groups in half, but I am clueless as to how that would work. For me, the mystery deepens when I measure pin 2 - L sideCV1: 3.4V.

I'll start a new thread and then come back and put a link to it here (now updated).

Oh, right - the ground pin - I could only find one pin that goes to the -ive terminal (Lside, pin 5). Did I make a newbie mistake here by identifying the ground and the -ive terminal?

Thanks for your help!

Looks correct to me. There are no newbie mistakes when figuring out pin outs on balance leads trial and error as long as nothing gets shorted out. You looked for pin outs , asked for help yep sounds good.
later floyd

Checking back on this post of the 9.8kWH LG ESS packs. How have everyone's experience with these? I was reading about fire risk with LG Chem modules. I'm only running mine from 3.5-4v now hopefully can mitigate this reported fire risk.